Micro-device for detecting volatile organic compounds, and method for detecting at least one volatile organic compound contained in a gas sample

Abstract

This invention relates to a micro-device for detecting volatile compounds comprising: an input (E) and an output (S); collection means ( 2 ) for taking a gas sample containing at least one compound to be detected; sampling means enabling a gas volume of 100 mL or less to be sampled, arranged after the collection means; injection means ( 3 ) of said gas sample; separation means ( 5 ) of the compound to be detected in the gas sample; compound detection means ( 6 ); and a gas circulation circuit ( 1 ) located downstream of the collection means and passing through the sampling means, injection means ( 3 ), separation means ( 5 ) and detection means ( 6 ); characterized in that the gas circulation circuit ( 1 ) has a volume of between 0.2 cm 3 and 2.0 cm 3 .

The invention claimed is: 
     
       1. Micro-device for detecting volatile compounds comprising:
 an input and an output; 
 a collection means for taking a gas sample containing at least one compound to be detected, arranged at the input of the micro-device; 
 a sampler enabling a gas volume of between 10 pL and 500 pL to be sampled, arranged after the collection means; 
 an injection means for injecting said gas sample, arranged after the sampling loop; 
 a separation means for separating the compound to be detected in the gas sample, arranged after the injection means; 
 a compound detection means, arranged between the separation means and the output of the micro-device, where the compound detection means is a photoionization micro-detector; and 
 a gas circulation circuit located downstream of the collection means and passing through the sampling loop, injection means, separation means and detection means, 
 wherein the gas circulation circuit has a volume of between 0.2 cm 3  and 2.0 cm 3 . 
 
     
     
       2. Detection micro-device according to  claim 1 , wherein the separation means of the compound to be detected are a gas-phase microchromatography device comprising a micro-column. 
     
     
       3. Method of detecting at least one volatile compound in a gas sample comprising:
 (i) collecting a gas sample containing the compound to be detected; 
 (ii) sampling the gas sample having a volume of 100 mL or less, said sampling being performed in a sampling loop; 
 (iii) injecting the sample taken in step (i) and sampled in step (ii) into means enabling the separation of the compound to be detected; 
 (iv) separating the compound to be detected, and 
 (v) detecting the compound, 
 
       said method optionally also including a step of injecting a vector gas at step (i) and/or (ii) and/or (iii) and/or (iv) and/or (v), 
       wherein the total vector gas consumption is between 0.1 mL/min and 5 mL/min. 
     
     
       4. Method according to  claim 3 , wherein the sampling step (ii) is performed using sampling loop having a volume of between 10 μL and 500 μL. 
     
     
       5. Method according to  claim 3 , wherein the method includes a step of pre-concentration after step (ii). 
     
     
       6. Method according to  claim 5 , wherein the sampling step (ii) is achieved using a sampling loop having a volume of between 0.5 mL and 100 mL. 
     
     
       7. Method according to  claim 5 , wherein the transfer of the sampled volume to the concentration means is achieved using a transfer gas at a flow rate of between 0.1 mL/min and 100 mL/min. 
     
     
       8. Method according to  claim 3 , wherein the separation of the compound to be detected in step (iii) is achieved using a gas-phase micro-chromatography device comprising a micro-column. 
     
     
       9. Method according to  claim 8 , wherein the vector gas used during separation by gas-phase micro-chromatography is selected from the group consisting of hydrogen, nitrogen, helium, argon and their mixtures. 
     
     
       10. Method according to  claim 8 , wherein the gas-phase micro-chromatography is performed with an elution flow rate of between 0.1 mL/min and 5 mL/min. 
     
     
       11. Method according to  claim 3 , wherein compound detection is achieved using a detector selected from the group consisting of a photoionization micro-detector (PID), a spectrometer for colorimetric detection, a katharometer, a flame ionization detector (FID), a mini- or micro-mass spectrometer, an acoustic detector and an infrared detector based on tunable laser diodes. 
     
     
       12. Method according to  claim 3 , wherein the volatile compound to be detected is selected from the group consisting of benzene, toluene, ethylbenzene, paraxylene, orthoxylene and metaxylene. 
     
     
       13. Use of the micro-device as defined in  claim 1  or of the method as defined in  claim 3  to detect compounds selected from the group consisting of benzene, toluene, ethylbenzene, paraxylene, orthoxylene and metaxylene.